Niš, less often spelled in English as Nish, is the third largest city in Serbia and the administrative center of the Nišava District. It is located in th…Niš, less often spelled in English as Nish, is the third largest city in Serbia and the administrative center of the Nišava District. It is located in the southern part of Serbia. According to the 2011 census, the city proper has a population of 182,797, while its administrative area has a population of 260,237 inhabitants.